1. Field of the Invention
This invention pertains to the field of pyrotechnic ordnance. More particularly, the invention pertains to propellants for ballistic projectiles. By way of further characterization, the invention pertains to a gun employing both solid and liquid propellants for launching projectiles.
2. Description of the Prior Art
Solid propellant guns have been used by modern armies and navies for many years in providing armament for conduct of war. This use of fixed ammunition where the projectile, the propellant and the igniter form a unitary structure is well known. Such fixed ammunition, while satisfactory for most purposes, suffers from certain well recognized drawbacks. Among the drawbacks are the required bulk and storage space which is highly disadvantageous where ammunition is stored in limited spaces such as when used in modern naval weapons and aircraft guns. Additionally, solid propellant fixed ammunition suffers from inherent chemical limitations of the solid propellants. Such propellants tend to be fuel-rich and result in unburned propellant which causes fouling and other weapon malfunctions.
A new class of liquid propellants has showed a great promise in developmental weaponry. However, to date, difficulties associated with liquid propellants have prevented their wide applications in the military environment. Propellants having the desired efficiencies to produce projectile velocities in the normal ranges are oxygen-rich and the heat of combustion of this oxygen-rich fuel has resulted in premature failure and damage to the breech blocking mechanisms and barrels of guns employing this fuel. Although designs have been proposed which minimize this metallurgical failure by employing alloys less susceptible to reactions with the propellant, these alloys have proved expensive, difficult to work, and frequently suffer from galling and other metallurgical failures.